package exsun.jt808.data.util;

/**
 * Created by CZ on 2018/9/18.
 */
public class MapUtil {

    private static double EARTH_RADIUS = 6371.393;
    private static double rad(double d)
    {
        return d * Math.PI / 180.0;
    }

    /**
     * 计算两个经纬度之间的距离
     * @param lat1
     * @param lng1
     * @param lat2
     * @param lng2
     * @return
     */
    public static double GetDistanceKm(String lat1, String lng1, String lat2, String lng2)
    {
        double radLat1 = rad(Double.valueOf(lat1));
        double radLat2 = rad(Double.valueOf(lat2));
        double a = radLat1 - radLat2;
        double b = rad(Double.valueOf(lng1)) - rad(Double.valueOf(lng2));
        double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a/2),2) +
                Math.cos(radLat1)*Math.cos(radLat2)*Math.pow(Math.sin(b/2),2)));
        s = s * EARTH_RADIUS;
        return s;
    }
    public static double GetDistanceM(String lat1, String lng1, String lat2, String lng2)
    {
        double radLat1 = rad(Double.valueOf(lat1));
        double radLat2 = rad(Double.valueOf(lat2));
        double a = radLat1 - radLat2;
        double b = rad(Double.valueOf(lng1)) - rad(Double.valueOf(lng2));
        double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a/2),2) +
                Math.cos(radLat1)*Math.cos(radLat2)*Math.pow(Math.sin(b/2),2)));
        s = s * EARTH_RADIUS;
        s = s * 1000;
//        s = Math.round(s * 1000);
        return s;
    }

}
